Electric generator.



M. ARENDT.

ELECTRIC GENERATOR. APPUCATION men MAY 28. I913.

1,237,272. Patented Aug. '21, 1917.

3 SHEETS-SHEET I.

lilllj-li INVENTOR %r/2/) fihwd/ TTORNE KS M. ARENDT. ELECTRIC GENERATOR. APPLICATION FILED MAY 28. 1913.

1,237,272. Patented Aug. 21, 1917.

- a SHEETS-SHEET 3.

' K1 WITNESSES N mvsnron Afar/a0 fire/70'? H M 61 fiffzdw z A TTORNEYS "UNITED STATES PATENT OFFICE};

MORTON minim, orrrnw YQBK, n. Y.

nnncrnrc ennnna'ron,

To all whom it may concern:

Be it known that ,I, Mormon Amanm', a citizen of the United States, residing at and whose post-office address is Ansonia-Hotel, Broadway and 7 3rd street, borough-of Manhattan, city, county, and State; of New York,.have invented certain new and useful Improvements in Electric Generators; and

I do hereby declare the following to be a full, clear, and exact description of the invention,'s'uch as will-enable others skilled in the art to which it appertains to make and use the same.

The invention ordiscove disclosed in the following descri tion, an illustrated-in the accompanying rawings, provides a direct current electric generator, having inherent capacity for self-regulation overa wide speed range suchthat it is well adapted,- without regulating adjuncts, to supply current to lightingsystems on vehicles such as motor cars,-boats, railway cars and the like,wherein thespeed of the driving source (the axle or the driving motor of'the vehicle is subject to frequent and abrupt variations over. a wide range. The self-regulatingcharacteristic of the generator in itspreferred form results primarily from the utilization within its structure of exaggerated unsymmetrical magnetic efiects and an electrically unbalanced armature. It is well known that a secondary battery connected across the terminals of a generator has an eflect,becau'se of its low internal resistance and hi h counter-electromotive force, sub- If the potential between themain bru es of such a generator is divided by an auxiliary brush so associated with the main brushes that armature conductors in the neutral zone (demagnetizing turns) are includedbetween the auxiliary brush and the leading main brush, while armature conductors in the active zone- (cross magnetizing turns) are included between the auxiliary brush and the trailing main brush, then as either the speed of the armature or the'armature current increases the potential difl'erence between the auxiliary brush and the leading main brush will progremively increase while the potential difference between the auxiliary brushand the trailing main brush will correspondingly diminish, and if the brushes are properly positioned as hereinafter described, the potential difference between the stem.

Specmcatlon'otLettera Patent. Pateht d A 21 1917 Application flied Kay 28, 1913. Serial No. 770,;63.

auxiliary brush the trailin main brush willfall' to zero and reverse. he result of,

this is that there exists between the auxiliary brush and the trailing main brush a potential difi'erence which s generall akm of anature suitable for producing lating excitation er the machine. y If the main field of the 'machine is excited with increase of speed ;.but I have found that if such generator is subjected to the wide s variations which may be expected of t e internal combustion engine of amotor car, for-example, the voltage generated will fall abruptly after a certain speed has been reached. That is to say, the range of autos matic regulation to the constant conditions required is not sufliciently wide. -.This

. brush and the trailin main brush, by providinga section'alize but electrically OOH? t'inuous excitin winding connected at its extremities to e main brushes in-th'e ordinaryshunt relation, and connected at an intermediate, point tothe auxiliary brush. Inasmuch as the increase of volta e between the auxiliary brush and'thelea ing main .brush is substantiallyequal to the decrease of voltage between. the auxiliary brush and the trailing main brush, the regulating effects of the two, when both are used for excitation purposes, might be expected to neutralize one another if the arrangement could may beextendedin severalways. Thus the uncreasm'g' voltage between. the, auxiliary be such that the changes of magnetic flux ultimately due to the variations of the two voltages were proportionate to these variations; but inasmuch as one voltage is falling and the other rising, the flux decrease wil necessarily exceed the flux'increase because of the changeof permeability due to greater or less saturation of the iron of the magnetic circuit. This predominance of the field-l lation over a range suchas'to constitute an entirely practical and valuable lighting generator" for the purposes indicated; particularly 'for1 motor car lighting in which the regulation of the lamps is not required to attain that degree ofaccuracy wh ch is'desir- I ation rnave-r und,roma neuiejm" of the generator'is'further impro'v if the eifects of the" unbalanced armature above doscrihed'ar'e supplementedym i of m creases the-fl emen-ca diagram-:-"of a 'geiierator"='cons't'ructe'd an operated. by *me' and-'which-represents the i m a ra'empba izjefaiiuiii"j "'te-theregu' lilting cli'cts er il wi ui iss armature arrangement, and which has "itself caanceotthe niagnet c circuitfofithe' jar-mature 'fluirb'g'; interposing" fieldframe and t interpole,'which iswithontianexcitin winde arfiiaturq'at on sid thereof," an

tanei'of feicircuitafthrpu direct {the l 'above deon" drawn"'-ato "scale" and a wirin bestrnode which I have contemplated applfing'the principles of my invention or discovery? i The diagram of Fig. 1 illustrates a machine having the usual field magnet structure' of thetwo pole'type and the usual-armaturcf together with the main brushes a and. bwhich are advanced in the direction of rota tionas illustrated together .with the auxiliaryibrush" sopla'ccdbn" tmc side of the' armature as to include between it and the leadingfmain brush be substantial numthat -ia-soain- 1 g pole and'de- F? in: under the-other in'ainpole as I gtothe accompan" draWin and 3"'- are"dia gs resentat ons-of difi'ereiit ifications illustratingvthdfhpfilicatidriof---the- :sereral feanirs'o in inreiitiom hnd -Figsiiki;51nd 6.; longitudiiial sectiom' a transmatic i' rep tween it and the leading main brush 6. F or' the purpose of prodm-ing close regulation over a wide speed range there is provided a sectionalized but electrical continuous field winding connected at its outer ends to the main brushes a b in the ordinary shunt relation and connected at an intermediate point to the auxiliary brush a. The sections of the field winding thus excited provide difl'erent excitation for the parts of the field struc ture so that to a substantial degree the falling of! in excitation current in the winding c, which is connected between the auxiliary '-brush' 0- and the trailing main brush a is counterbalanced by the increase of excitationcurrent in the winding 6' connected between the auxiliary brush 0 and the leading -main. brush 6. Because of the effect of maghetic saturation of the iron of the magnetic jcirc'uifi' however, the decrease in flux will sult will beia diminutionof the total field when either the speed of rotation of the are the increase in flux and the final reiii'aturo 'or thej armature current increasesment of the field mag- 'iofiect of this interpole is to reduce the re- "luctance ofthe magnetic circuit .of the armature-flux, and at the same time to unbalance of the flux to one side of thearmature.

mice that circuit so as to draw a -preponder- The result is that as the armature current increases the increasing armature-flux is so 'led into the main poles as to brin about a -'decrease of the flux over the who e face of the trailin niain pole and an increase-of the jflux over t e whole face of the leading main pole,- the decrease exceeding the increase and therebyeifectinga substantial regulation givinga'slowly rising current characteristic. -If, the-- armature winding be of the Grammering type, or of the multiple circuit-drum-type which is ossible in a multipolar" machine, theun alancin of the magnetic-field will further result in an unbalancing of the current in the different-sectionsof the armature winding, giving an effect similar to the unbalanced electrical conditions present when'the auxiliary brush a is' used. v V In the arrangement illustrated in Fig. 3 the unbalanced magnetic structure of Fig. 2

is combined with the electrically unbalanced armature arrangement of Fig. 1 so that the combined effects above described are obtained. In this combined arrangement, -hcrcforc. the magnetic flux in the portions of the ari'naturc core dominated by the difrent .nnin poles has different strengths an-l varies at different rates; while the portion dominated by the interpole has still another .value and another rate of variation, and the effect of this unsymmetrical field structure is increased by the provision of a sectionalized exciting winding carrying currents which vary in such manner as to intensify the self-regulating'efiect of the unsymmetrical field. The result is to produce a stable generator having an inherent characteristic of self-regulation over a very wide range of operative conditions.

The specific generator illustrated in Figs. 4, 5 and 6 has a cast steel field frame 3 to which are bolted in radial disposition the 2 two main poles 4 and 5 and the interpole 6.

-ment about the armature shaft.

The shunt field windings 22 and 25 are provided each with 300 turns of 19 B. & S. gage wire. The series coils 21.and 24' comprise respectively 7 and 21 turns of No. 19 B. & S. wire, and resistance 28 has a value of about one and one-quarter (111-) ohms. -'T he armature 1 is of the ordinary toothed core-type having thirty (30) slots, "a.ndcarries a usual form of drum winding consisting of 360 mductors;-of No. 16 B; & S. wire wound in thirty (80) coils. Thiswinding is connected to an ordinaryiorm of commutator having thirty (30) commutator bars, and upon which bear ordinary main collector brushes 12 and 13 and an auxiliary brush 14'so located as to include between it and the leading main brush 12 those armature coils which are dominated by the interpole and through which the armature flux passes. These brushes 12, 13 and 14 are mounted upon the brush holder ring 11 which is concentric with and. capable of angular ad ust- The brush 14 is supported from ring 11 by slotted connection 7 (see Fig. 4) so that its displacement with respectto the main brush 12 may readily be adjusted. The usual displace ment is two and one-half (2%) to three (3) commutator segments.

The poles 4 and 5 are diametrically disposed, lmt the shoes thereof are each unsymmetrical, the arrangement being such that the adjacent ends 15 and 17 of the ole pieces have a greater angular extent t an the other ends 16 and 18, so that the space between the pole tips 15 and 17 in which interpole 6 is located. is of lesser angular extent than the space between the pole tips 16 and 18. so as to exaggerate the magnetic leakage on that side of the armature; Furthermore, the pole 4 is slotted as at 19 to give a reluctance higher than that of pole 5. The windings 22 and 25 are connected in electrical series with each other across the main brushes 12 and 13, in shunt relation to the external circuit containing the incandescent lamps 26- and the battery 27, while the third brush 14 is connected through the exciting winding 23 to a point intermediate the windings 22 and 25. The storage battery 27 is connected in series with one portion 24 of the series exciting winding across the brushes 12, 13 and the otherportion 21 of the series exciting winding is connected in series with the lamps. The resistance 28 is inserted between the connection to the third brush 14 and the exciting winding 22 for the direction of rotation indicated by the arrow in Fig. 6. The system is also provided with the automatic voltageswitch '29 adapted to connect the generator to the battery. when the voltage of the generator reaches a sufiicient value, and the switch 30 is provided for switching the lamps 26 in and out of circuit. The lamps may also. have their individual switches. f

The shunt field coils 22 and 25 cofiperate to produce the efi'ective field flux at low speeds, and at the high range of speed, after the current in coil 25 has reversed, the ma .netomotive forces of these coils oppose eac other. Auxiliary coil 23 is so connected to auxiliary brush 14 that it at first coiiperates with the predominating field, but at higher speeds, when the potential difi'erence between brushes 12 and. 14 exceeds that between 12 and 13, it opposes the malnetizing effect of coil 22; and this action increases with increase of potential difference between brushes 12 and 14. The series field winding of relatively few turns, comprising coils 21 and 24 is connected in its entirety between one terminal of battery 27 and-one of load 26, in such a manner that the lamp current through coils 21 and 24 is efi'ective to fix the-polarity of the generator to conform with that of-the battery. The connection of main brush 13 to this samewinding is such that when the generator sup-.-

ture and scope of my invention will be understood. The description has been restricted to two-pole machines for the sake of simplicity and. because the particular machine illustrated in Figs. 4, 5 and 6 wasso designed, but as all electrical engineers will understand the invention may be embodied in bulk may be compensated by slight variation of the angular displacement of brush 14 with respect to brush 12 or by a slight change of the resistance 28, or by both.

In case the machine is to be driven from a car axle so that the direction of rotation is subject to reversal, field coil 23 and slots 19 are omitted and provision is made for rotating the main brushes through 180, and for moving the auxiliary brush to the other side of the interpole region, the main brush and the auxiliary brush being mounted on separate brush holder rings for this purpose.

'What I claim is:

1. A dynamo-electric machine having an armature with'a distributed winding and a many part commutator, main commutator brushes for collecting the work current; said main brushes being advanced from the geometrical neutral position, and an auxiliary brush, the brushes being so located on the commutator as to include between the auxiliary brush and the leading main brush the zone of armature conductors lying adjacent the axis of the armature field. a sectionalized but electrically continuous exciting winding for the machine, one portion of the exciting winding being connected between the auxiliary brush and the leading main brush and another portion being connected :between the auxiliary brush and the trailing main brush! i 2. A dynamo-electric machine having an' armature with a distributed winding and a many part commutator, main commutator brushes forcollecting the work current, and an auxiliary brush; the brushes being so located on the commutator as to include between the auxiliary brush and the leading main bruslr-the zone of armature conductors lying adjacent the axis of the arma ture field. a sectionalized but electrically continuous exciting winding for the machine, one portion of the exciting winding being connected between the auxiliary brush and the leading main brush and another portion being connected between the auxiliary brush and the trailinganain brush and the circuit connecting the auxiliary brush with the leading main brush having a greater electric resistance than the circuit connecting the auxiliary brush with the trailing main brush.

3. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, main commutator brushes for collecting the work current, and an auxiliary brush, the brushes being so located on the commutator as to include between the auxiliary brush and the leading main brush the zone of armature conductors lying adjacent the axis of the armature field, a sectiona-lized but electrically exciting winding for the machme and separate field structure elements ofdifferent magnetic reluctance on which the sections of the exciting winding are wound, that portion of the exciting winding which is on the field structure element of less magnetic reluctance being connected between the auxiliary brush and the trailing main brush and that portion of the exciting windingwhich is on the field structure element of greater magnetic reluctance being connected between .the auxiliary brush and the leading main brush.

4. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, main commutator brushes for collectin the work current, and an auxiliary brush, t e brushes being so located on the commutator as to include between the auxiliary brush and the leading main brush the zone of armature conductors lying adjacent the axis of the armature field, a sectionalized but electrically continuous exciting winding for the machine and separate field structure elements of different magnetic reluctance on which the sections of the exciting winding are wound, that portion of the exciting winding which is on the field structure element of less magnetic reluctance being connected between the auxiliary brush and the trailing main brush and that portion of the exciting winding which is on the field structure element of greater magnetic reluctance being connected between the auxiliary brush and the leading main brush and the circuit connecting the auxiliary brush with the leading main brush having a greater electric resistance than the circuit connecting the auxiliary brush with the trailing main brush.

5. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, an unsymmetrical field structure in which the magnetic reluctance of the armature flux path is substantially reduced bctwccn alternate main poles,

main commutatorbrushes for collecting the continuousin which the magnetic reluctance of the armature flux path is substantially reduced between alternate main poles, main commutator brushes for collecting the work current, and a shunt'exciting winding for the field structure. 7

7 A dynamo-electric machine having an armature with a distributed, winding and a many part commutator, an unsymmetrical field structure in which the magnetic reluctance of the armature-flux path is substantially reduced between alternate mam poles, main commutator brushes for collecting the work current, and an auxiliary brush, the brushes being so located on the commutator as to include between theauxiliary brush and the leading main brush the zone of ar mature conductors lying adjacent the axis of the armature field, and an exciting winding for the field structure connected between the auxiliary brush and the trailing main brush.

' 8. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, an unsymmetrical field structure in which the magnetic reluc-- tance of the armature flux path is substan tially reduced between alternate main poles, main commutator brushes for collecting the work current, and an auxiliary brush, the brushes being so located on the commutator as to include between the auxiliary brush and the leading main brush the zone of ar mature conductors 1 ing adjacent the axis of the armature fie d, a sectionalized but electrically continuous excitingwinding for the field structure, one p'ortionof the exciting winding being connected'between the auxiliary brush and the leading main brush, and another portion being connected be-" tween the auxiliary brush and the trailing main brush,

9. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, an unsymmetrical field structure in which the magnetic reluctance of the armature flux path is substantially reduced between alternate main poles, main commutator brushes for collecting the work current, and an auxiliary brush, the brushes being so located on the commutator as to include between the auxiliary brush and the leading main brush the zone of ar-. mature conductors lying adjacent the axis of the armature field, a sectionalized but electrically continuous exciting winding for main brush.

. connected the field structure, one portion of the exciting winding being connected between the auxiliary brush and the leading main brush,

and another portion being connected between the auxiliary brush and the trailing main brush, and the circuit connecting the auxiliary brush with the leading main brush having a greater electric resistance than the circuit connecting the auxiliary brushwith the trailing main brush.

10. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, an unsymmetrical field structure having main field magneticcircuits of difierent magnetic reluctance and in which the magnetic reluctance of the armature flux path is substantially reduced between alternate main poles, main commu 'tatorbrushes for collecting the work current, and a sectionalized but electrically con' tinuous exciting winding for the difierent main field magnetic circuits, that portion of the" exciting winding which directly excites the main field circuit of less magnetic reluctance being connected between the auxiliary brush and the trailing main brush and that portion of-the exciting winding which, directly excites the main field circuit of greater magnetic reluctance being connected be tween the auxiliary brush and the leading 11. A dynamo-electric machine havingan armature with a distributed. winding" and a many part commutator, an unsymmetrical field structure having main field magnetic circuits of different magnetic reluctance and in which the magneticreluctance of the armature flux path is. substantially'reduced between alternate main poles, main commutator brushes for collecting the work ourrent and a sectionalized but electrically continuous exciting winding for the difl'erent main field magnetic circuits, that portion of the excitin winding which directly excites the main eld circuit of less magnetic reluctance being connected between the auxiliary brush and the trailing main brush and that portion of the exciting winding which directly excites the main field circuit of greater magnetic reluctance bein etween the auxiliary brush and the leading main brush, and the circuit connecting the auxiliary brush. with the leading main brush having a greater electric resistance than the circuit connectingthe auxiliary brush with the trailing main brush.

12. A dynamo-electric machine having an armature with a distributed winding and a many part commutator, main commutator brushes for collecting the work current, and

an auxiliary brush, the brushes being so located on the commutator as to include be tween the auxiliary brush and the leading main brush the zone of armature conductors U ized shunt exciting winding. 4

' 13. The combination with a generator having main collecting brushes and an auxiliary brush, a shunt exciting winding connected to the auxiliary brush, anda sectionalized' series exciting winding, j of a battery and a translating device supplied from the generator, onesection of, the series winding being connected across the-main brushes in series. with the translating device, andthe other. section of theseries winding being cpnnected the mainbrushes in series with the batte 14.

: ing main collectinfizbrushesand an auxiliary brush, a sectiona nected to the auxiliary brush, and. sectionalized series exciting ofa battery 1 and a translating device sup'p 'ed' from the,

crater, one section of the series winding eing connected across the main brushes in series with the-translating device, and the other section of theseries winding-being connectedacross the main'brushes 111' series with the battery. a

15. A dynamo electric machine having an armature with a distributed winding and a many ,part commutatoigyan unsymmetrical field structure in which the magnetic reluced shunt field winding. connected to the main brushes and also conin presence oftwo' mam-m tance of the arhnattire flux path is substan tially reduced between alternate main poles, main commutator brushes for collecting-the work current, and an auxiliarybrush, the brushes being 50 located on the commutanected' across the main brushes in series.

with the translating device and another'section connected across the main brushes in la a r series with the battery.

he combination with a generator hav-' 16. A; dynamo electric machine having an armature with a distributed winding and a many part commutator, an unsymmetrical lfield structure comprising main field poles with unsymmetrical pole shoes producing alternate spaces'between the pole shoe tips of difl'erent extent, and an-unwound interpole in the smallerinterpolar space, .main

-. tor as to include between the auxiliary brush commutator brushes for collecting the work 4 current, and an .excitingwinding for the field structure. f i i 'In testimony whereof witnesses. MORTON ARENDT. Witnesses: r M.A.-Bn.r., 1

LEON RosnN'rHAL.

I afiix my signature, 

